The present invention relates to inflatable cushions for chairs and to valves therefor. Inflatable seat and chair cushions have typically included a seat cushion having a plurality of inflatable compartments which are positioned at various points along the chair back or seat portion. Each inflatable cushion is selectively inflatable so as to increase or decrease the firmness of various parts of the chair cushion.
Inflatable chair cushion assemblies have heretofore had serious drawbacks which have hindered their widespread acceptance. Some are provided with a valve structure which connects each of the pressurized compartments with a common exhaust manifold with no means for preventing pressurized fluid from one compartment from escaping from that compartment, flowing through the manifold and pressurizing another compartment. Therefore, all of the compartments will eventually have the same pressure, making it difficult to selectively adjust the pressure in each of the cushions for selective body support.
In other assemblies, each of the cushion compartments is connected to a common pressure manifold with check valves between the manifold and each of the cushion compartments to prevent one cushion compartment from inflating another. However, with check valves, the pressure manifold is connected to a common source of pressure which will inflate each of the cushions to the same pressure. If a master pressure control valve is provided between the constant pressure source and the common pressure manifold, then in order to fill each compartment to a desired pressure different from the others, the user must (1) adjust the master control valve such that the delivered pressure is the pressure of the cushion to have the highest pressure; (2) fill all of the cushion compartments to that presure; (3) readjust the master control valve such that the pressure delivered is no more than that of the cushion compartment to have the lowest pressure; and then (4) exhaust air from each of the cushion compartments selectively through exhaust valves associated with each cushion compartment to obtain the desired pressure differences among the cushion compartments. Thus, several valves must be operated to fill each cushion compartment to a pressure different from the others. This operation procedure is unduly complicated, especially if the inflatable seat cushion assembly is to be used in an automobile where the driver's concentration must be focused on where he is going, not on the subtleties of operating a complicated inflatable seat cushion.
There are inflatable seat cushions which are easier to operate than those described above, but they are mechanically complicated. For example, an inflatable seat cushion assembly wherein each of a plurality of seat cushion compartments can be adjusted simply by turning a lever-like slide valve has been disclosed. However, the slide valves are extremely complicated to construct. Each of the slide valves employs a plurality of opposed springs to hold the valve slide member in a proper position. Furthermore, microswitches are provided for each of the slide valves to operate an air compressor each time one of the slide valves is moved to the "fill" position. Therefore, such designs are impractical to construct.
Examples of prior patented inflatable seat cushions may be found in U.S. Pat. No. 4,078,842 entitled Kit for Inflatable Full-Length Body Supporting Seat, issued on Mar. 14, 1978 to Zur; U.S. Pat. No. 3,363,941, entitled Air Inflated Automobile Seat, issued on Jan. 16, 1968 to Wierwille; and U.S. Pat. No. 3,326,601, entitled Inflatable Back Support for a Seat, issued on June 20, 1967 to Vanderbilt. A need exists for an inflatable seat by which the aforementioned problems are solved.